1. Field of the Invention
The present invention relates to a bed-leaving sensor that detects bed-leaving by a user on a bed, and a bed-leaving detection method.
2. Description of the Related Art
For example, in a hospital, nursing facility or the like, when a care receiver such as a physically disabled patient, an elderly person or the like who is in bed tries to get out from the bed by himself, there is a risk of tumbling or falling down. In light of that, examination has been done of aiding a care receiver with leaving the bed by using a bed-leaving sensor for detecting bed-leaving when the care receiver leaves the bed, and when it is detected by the bed-leaving sensor that the care receiver is leaving the bed, a caregiver is notified.
As this kind of bed-leaving sensor, in Japanese Unexamined Patent Publication No. JP-A-2012-29871, proposed is a bed-leaving sensor for which a pressure sensor is arranged on a bed, and when the body pressure of the user detected by the pressure sensor is a designated value or less, it determines that the person left the bed. Also, in Japanese Unexamined Patent Publication No. JP-A-2012-11174, proposed is a bed-leaving sensor for which a load sensor is provided at each leg part, and when the movement volume of the load center of gravity detected by those load sensors goes to a designated value or less, it determines that the person left the bed. However, with the bed-leaving sensors noted in JP-A-2012-29871 and JP-A-2012-11174, bed-leaving is detected after the user has completely left the bed, so the detection timing is slow, and there is the risk of an accident such as the person having fallen down or the like already having occurred when the caregiver rushed to check.
Meanwhile, in Japanese Unexamined Patent Publication No. JP-A-2007-313189, proposed is a movement discrimination device for detecting that the user has sat up based on the movement volume and movement direction of the user's body center of gravity. However, with the movement discrimination device noted in JP-A-2007-313189, since it is determined a person has left the bed only by the user sitting up, there is a high risk of false alarms, with bed-leaving detected even when it is simply sitting up unrelated to leaving the bed, and in addition to there being a high risk of false alarms, the detection timing is early, and there is a risk of the caregiver being called frequently.